Clinical efficacy of irinotecan plus raltitrexed chemotherapy in refractory esophageal squamous cell cancer

Efficacy and safety of irinotecan combined with raltitrexed or irinotecan monotherapy for salvage chemotherapy of esophageal squamous cell cancer: A prospective, open label, randomized phase II study

BACKGROUND

Esophageal squamous cell cancer (ESCC) accounts for approximately 90% of esophageal cancer cases in China. There are no standard regimens for second or third-line chemotherapy of metastatic squamous esophageal cancer. The objective of this study was to investigate the security and effectiveness of irinotecan combined with raltitrexed or irinotecan monotherapy for salvage chemotherapy of ESCC.

METHODS

One hundred and twenty-eight patients with metastatic ESCC confirmed by histopathology were enrolled into this study. These patients had failure of the first-line chemotherapy combination of fluorouracil or platinum or paclitaxel and had not undergone chemotherapy with irinotecan or raltitrexed previously. Patients were randomly divided into irinotecan combined with raltitrexed group (experiment group) and irinotecan monotherapy group (control group). Overall survival (OS) and progression-free survival (PFS) were the primary endpoint.

RESULTS

In the control group, the median PFS (mPFS) and median OS (mOS) of patients were 3.37 and 5.3 months. In the experiment group, mPFS and mOS were 3.91 and 7.0 months. There was statistical significance of PFS and OS between two groups (PFS P = 0.002, OS P = 0.01). In subgroup analysis, in the second-line treatment, the mPFS of control and experiment group, was 3.90 and 4.60 months, mOS was 6.95 and 8.5 months, which was statistically significant differences between the two groups. (PFS P = 0.001, OS P = 0.005), In the third-line and beyond treatment, mPFS of control and experiment group was 2.80 and 3.19 months, mOS were 4.5 and 4.8 months. But there was no significant difference of PFS or OS between the two groups (PFS P = 0.19, OS P = 0.31). There was no statistical significance of toxicity side effects between two groups.

CONCLUSIONS

The PFS and OS of irinotecan plus raltitrexed may be better than that of irinotecan monotherapy, especially in second line treatment, which should be confirmed with a phase III study including much more patients.

Mechanisms of Pharmaceutical Therapy and Drug Resistance in Esophageal Cancer

Pharmaceutical therapies are essential for esophageal cancer (EC). For the advanced EC, the neoadjuvant therapy regimen, including chemotherapy plus radiotherapy and/or immunotherapy, is effective to achieve clinical benefit, even pathological complete response. For the unresectable, recurrent, and metastatic EC, the pharmaceutical therapy is the limited effective regimen to alleviate the disease and prolong the progression-free survival and overall survival. In this review, we focus on the pharmaceutical applications in EC treatment including cytotoxic agents, molecular targeted antibodies, and immune checkpoint inhibitors (ICIs). The chemotherapy regimen is based on cytotoxic agents such as platinum-based complexes, fluorinated pyrimidines and taxenes. Although the cytotoxic agents have been developed in past decades, the standard chemotherapy regimen is still the cisplatin and 5-FU or paclitaxel because the derived drugs have no significant advantages of overcoming the shortcomings of side effects and drug resistance. The targeted molecular therapy is an essential supplement for chemotherapy; however, there are only a few targeted therapies available in clinical practice. Trastuzumab and ramucirumab are the only two molecular therapy drugs which are approved by the US Food and Drug Administration to treat advanced and/or metastatic EC. Although the targeted therapy usually achieves effective benefits in the early stage therapy of EC, the patients will always develop drug resistance during treatment. ICIs have had a significant impact on routine clinical practice in cancer treatment. The anti-programmed cell death-1 monoclonal antibodies pembrolizumab and nivolumab, as the ICIs, are recommended for advanced EC by several clinical trials. However, the significant issues of pharmaceutical treatment are still the dose-limiting side effects and primary or secondary drug resistance. These defects of pharmaceutical therapy restrain the clinical application and diminish the effectiveness of treatment.